The present invention relates to heat transfer mechanisms, and more particularly, to heat transfer mechanisms and cooling assemblies for removing heat generated by an electronic circuit module.
The efficient extraction of heat from electronic circuit modules for very large scale integrated circuit packages has presented a significant limitation on the design and use of such electronic modules. The power consumed in the integrated circuits generates heat which must in turn be removed from the package. Lacking an efficient heat transfer mechanism, the speed, reliability and power capabilities of the electronic circuit modules are limited. As the density of circuitry within very large scale integrated circuit chips has increased, the need for improved heat extraction has become even more acute since more densely packed chips tend to have a higher need for heat dissipation per unit area. It is also known that runaway thermal conditions and excessive heat generated by chips is a leading cause of failure of chip devices. Furthermore, it is anticipated that demand for heat removal from these devices will continue to increase indefinitely. Accordingly, it is seen that there is a significant need to continue to further improve upon cooling mechanisms for electronic devices.
Technology is fast approaching the limits of direct air cooling technologies (e.g., air cooled heat sinks), when applied to electronic modules such as large server processors. Liquid cooling technologies are believed to provide enhanced heat removal when air cooling technologies have reached their limits. Jet impingement of liquid coolant is one method of liquid cooling wherein a jet of coolant liquid impinges upon a flat surface. The advantage of jet impingement is that it is relatively simple to implement (i.e., low cost), and effective. Described herein is an enhanced jet impingement technique which extends the thermal performance of a jet impingement assembly by as much as forty percent or more. Specifically, the present invention proposes modifying the impingement surface to obtain both an improvement in the heat transfer characteristics of the cooling jet to impingement surface, and an increase in the surface area for heat transfer.
To briefly summarize, the present invention comprises in one aspect a cooling assembly for an electronic module. The cooling assembly includes a thermally conductive plate having a first main surface and a second main surface with at least one concave surface portion formed in the second main surface extending towards the first main surface. Each concave surface portion has a conic section profile. At least one jet nozzle is disposed above the at least one concave surface portion defined in the second main surface. Fluid introduced into each concave surface portion through a respective jet nozzle impinges upon a lower portion of the concave surface portion and flows outward along the concave surface portion. In practice, the conic section profile comprises one of an elliptical section, a circular section or a parabolic section.
In other aspects, the present invention comprises methods of fabricating a cooling assembly such as described above, as well as a cooling assembly and electronic module stack which employs a cooling assembly as summarized above.
To restate, various enhanced cooling assemblies with thermally conductive plates having concave surface portions with conic section profiles are presented herein. The conic-sectioned plate is disposed below multiple jet nozzles which impinge jets of fluid into the concave surface portions. The cooling assemblies presented herein facilitate the removal of heat from a structure, such as an electronic circuit module. These assemblies enhance the ability to remove a large amount of heat with a low temperature difference. Further, the assemblies presented are compact and modular in design.
Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention.